Folding chair assembly



Jan. 11, 1966 o. w. BAROFSKY 3,223,723

FOLDING CHAIR ASSEMBLY Filed Feb. 7, 1964 2 Sheets-Sheet 1 FIG.4

FIG. 6

INVENTOR.

ORIS W. BAROFSKY 7 3104, dw z w ATTORN EYS Jan. 11, 1966 o, w. BAROFSKY 3,228,723

FOLDING CHAIR ASSEMBLY Filed Feb. 7, 1964 2 Sheets-Sheet 2 42 34 l g 40 32 112M! 2 lil a FIG. 8 30 70 4 INVENTOR. I. ORIS w. BAROFSKY l E QWfW ATTOR NEYS United States Patent 3,228,723 FOLDING CHAIR ASSEMBLY Oris W. Barofsky, Menominee, Mich, assignor to Heywood-Wakefield Company, Gardner, Mass., a corporation of Massachusetts Filed Feb. 7, 1964, Ser. No. 343,272 3 Claims. (Cl. 297-35) This invention relates to. seating units and more particularly to a folding chair assembly for use in auditoriums, arenas and the like.

The seating facilities in auditoriums, arenas, gymnasiurns and similar public places can be divided for purposes of classification into two general categories which are distinguishable by the relative permanence of the particular seating installation. The first category includes the substantially permanent chair installations employed in school auditoriums, theaters, movie houses and similar public halls. The seating installations in these places usually comprise units of two or three or more chairs secured together and fastened to the fioor by means of bolts or similar fastening means. Although these units can be removed from the theater or auditorium, their removal entails a considerable expenditure of time and labor, and hence is a costly and infrequent operation.

In contrast to the relatively permanent theater type chair installations, there are numerous examples of so called temporary and portable seating installations. Familiar examples would of course include the ubiquitous folding chair and the temporary bleacher installations found in school gymnasiums and occasionally on the football field.

The temporary seating installations, as the name implies, are designed to provide temporary seating facilities which can be disassembled after use and stored in some convenient location until they are needed again. The primary advantage of temporary seating facilities, in contrast to the more permanent installations, is the comparative ease with which a public space can be converted from one activity to another. For example, the bleachers in a high school gymnasium can be dismantled and removed to provide a considerably enlarged area for dances and other events which require the full floor space of the gymnasium. However, even the erection and dismantling of portable bleachers and similar temporary installations are time-consuming and laborious operations which require the services of a number of persons and therefore are relatively expensive. With the rising cost of labor, it is apparent that the inherent advantages of temporary seating arrangements have been partially negated.

Recently a compromise seating arrangement has gained considerable acceptance for use in school gymnasiums and similar multiple purpose public areas. The new seating arrangement utilizes the best features of both the temporary and permanent seating installations and is descriptively termed a telescoping bleacher or stand. Each riser section of the telescoping bleacher is mounted on wheels or rollers so that the entire bleacher can be telescoped into a narrow vertical storage unit or pushed back against a wall. Since the telescoping action of the bleacher sections allows the bleachers to be stored in a relatively narrow area, this seating arrangement affords the maximum utilization of floor space with a concomitant minimum expenditure of labor and money.

The principle of telescoping seating facilities can be adapted to other multiple purpose areas besides gymnasiums. In such cases, it is usually desirable to have a more comfortable seating arrangement than that provided by the flat boards of a bleacher. Theater type ice paddled chair assemblies can be mounted on telescoping bases in the same manner as bleacher seats, but the number of rows of chairs is severely limited by the vertical space requirement imposed by the construction of a conventional chair. However, if each row of chairs can be folded into a substantially horizontal position, the number of chair rows for a given telescoping assembly can be increased appreciably. It is therefore a primary object of the present invention to provide a folding chair assembly for use in telescoping seating facilities.

It is another object of the invention to provide a folding chair assembly which has a low silhouette and which occupies a minimum amount of vertical space in its folded position.

It is still another object of the invention to provide a multiple-unit folding chair assembly which can be operated by a single person.

It is a further object of the present invention to provide a multiple-unit folding chair assembly which is securely retained in its operative position yet can be folded easily into storage position or tilted forward to provide access for cleaning, maintenance and other purposes.

These objects and other objects of the invention will best be understood and appreciated from a more detailed description of the preferred embodiment thereof, selected for purposes of illustration, and shown in the accompanying drawing in which:

FIG. 1 is a perspective view of a multiple unit folding chair assembly;

FIG. 2 is a diagrammatic side elevation of the telescoping seating installation;

FIGS. 3-6 are perspective views from the side showing the sequential opening of the chair assembly from its horizontal storage position to its fully upright seating position;

FIG. 7 is a view in perspective showing the multiple unit chair assembly tilted forward for cleaning and other maintenance purposes; and,

FIG. 8 is a perspective view showing a single chair of the multiple-unit folding chair assembly.

Turning now to the drawings, FIG. 1 depicts in perspective a multiple-unit folding chair assembly indicated generally as 2 which is shown in its unfolded seating position. The chair assembly 2 as shown seats three people, however, the novel features of the disclosed folding chair assembly are equally applicable to single chairs as well as to multiple units, and hence, it is not intended to limit the invention to a particular number of seating units.

The multiple-unit folding chair assembly 2 is mounted on a base indicated generally as 4. The base 4 represents the horizontal portion or tread of a telescoping stand 6 shown diagrammatically in FIG. 2. The telescoping stand 6 is depicted in its extended position with chairs 8 fully erected in each row. When his desired to push the stand back into its wall storage compartment 10, the chairs 8 are collapsed and the stand is telescoped in the direction shown by the arrows in FIG. 2.

The folding chair assembly 2 is constructed in a conventional manner with regard to its seating function. Thus each individual seating position has a chair back 12, chair seat 14 and arm rests 16. It is a feature of the folding chair assembly that from the standpoint of the occupant, the chair provides a degree of comfort which is normally associated only with fixed theater type chair installations. The chair seat 14 and the chair back 12 are both padded with a suitable cushioning element such as polyurethane foam and are upholstered with one of the well known conventional covering materials. Although the width of the seat 14 and height of the chair back 12 conform to the standard dimensions employed in the seating industry, these dimensions can be varied to accommodate the requirements imposed by a particular seating installation. In addition to meeting the dimensional standards in the seating industry, the folding chair assembly 2 also conforms to the normal degree of back pitch and seat pitch. These features of the folding chair assembly 2 have been mentioned to emphasize the fact that folding chair assembly 2 is essentially the equivalent of a conventional theater type fixed chair installation and as such provides the occupant with the same comfortable seating support expected from a theater chair. However, the folding chair assembly 2 has a critical difference i.e., it can be folded from an upright or seating position into a horizontal or storage position.

The collapsible feature of the folding chair assembly 2 is illustrated in FIGS. 3-6 which depict the sequential opening of the chair assembly from its storage position (FIG. 3) to its upright or seating position (FIG. 6). It is a feature of the folding chair assembly 2 that in its storage position the chair assembly has a compact and low silhouette. As mentioned previously, the low silhouette of the chair assembly permits an appreciable increase in the number of horizontal rows of chairs which can be telescoped and stored in a given vertical space. The elements of the folding chair assembly 2 and the cooperative relationship therebetween which produce the compact silhouette will be discussed after a brief description of the opening and erection of the chair assembly.

Referring now to FIGS. 3 through 6, the sequence of opening the chair assembly 2 is shown therein with the direction of movement of the various components of the chair assembly indicated by arrows in the respective figures. Looking specifically at FIG. 3 it can be seen that if the chair back 12 is grasped by its upper edge 18 and lifted upwardly, the upper edge 18 will follow an arcuate path shown by the arrow in FIG. 3. After the chair back 12 is raised to the intermediate position shown in FIG. 4, the direction of movement is changed by pushing backwardly on the upper edge of the chair back 12 thereby causing the upper edge 18 to trace a generally arcuate path in an upward and rearward direction as shown by the arrow in FIG. 4. When the chair back 12 reaches the substantially vertical position depicted in FIG. 5, the upper edge 18 of the chair is pushed downwardly and rearwardly until the chair locks in place as shown in FIG. 6.

Having thus described the unfolding of the chair as sembly 2, I will now discuss in detail the structure of the chair assembly and the folding mechanism thereof. The chair assembly or single chair unit as the case may be, is constructed around an H-shaped frame indicated generally as 20. The frame 20 consists of two upright members 22 and 24 which are maintained in spaced relation by a gently curved cross bar 26, a portion of which is visible in FIG. 1 and which is clearly shown in FIG. 7. The chair back 12 is secured to and between the upright members 22 and 24 and projects a substantial distance above the upper extremities thereof. The chair back 12, upright members 22 and 24, and cross bar 26 as depicted formv an integral unit having a considerable degree of structural rigidity. The strength and rigidity of this unit greatly simplifies the opening and closing of the chair assembly because the necessary force can be applied to the readily accessible edges of the chair back 12 instead of to the less accessibleframe 20. Referring back for a moment to the previous explanation of the opening of the chair assembly 2, it should be noted that the entire opening force was applied to the upper edge 18. of chair back 12. The chair assembly 2 is closed in a similar manner except that the lower edge 28 of the chair back 12 is grasped and pulled towards the operator. It is thus possible to both open and close the chair assembly from the front of the assembly merely bypulling or pushing on the stallation with a concomitant reduction in labor cost involved in these operations.

The structural relationship between the chair assembly 2 and the base member 4 is shown in all of the figures, however, the following discussion can best be understood by referring specifically to FIGS. 3 and 4. The chair assembly 2 is pivotally mounted on base 4 by means of links 30 which are secured to a pivot rod 32 journalled in base journals 34. The upper ends of links.30 are pivotally secured to the corresponding upright members of each seating unit. The pivotal connection between the links 30 and upright members 22 and 24 can be accomplished in a variety of conventional ways known to those skilled in the art. In the embodiment of the chair assembly 2 shown for purposes of illustration, the links 30 are pivotally mounted in a U-shaped bracket 36 which cx tends outwardly and forwardly from each upright member. Since the bracket 36 is either integrally fabricated with the upright member or rigidly mounted thereon, mechanically the links 30 are pivotally secured to the upright member and the folding chair assembly 2 can be defined in terms of an upright member and a link pivotally secured thereto.

The pivotal action of pivot rod 32 within base journals .34 and the concomitant movement of the chair assembly itself has been described previously with respect to the sequential opening of the chair assembly shown in FIGS. 4-6. However, it should also be noted that the pivotal movement of the rod 32 allows the chair assembly to be tilted forward as shown in FIG. .7. With the chair assembly in the tilted position, the entire underneath surface of the chair assembly and the corresponding base area are exposed for cleaning, repair and any other maintenance work which may be required.

Each seating position as mentioned previously is pro vided with a chair seat 14 and a pair of arm rests 16 although in multiple installations the intermediate arm rests will of course serve as a common arm rest for two seating positions. .The chair seat 14 is secured to and supported by two L-shaped arms 38 pivotally connected to a bracket '40 which is rigidly mounted on each of the upright members. The forward projection of bracket 40 and the location of the chair supporting arm pivot point in the bracket aredesigned to permit the chair back 12 to overlie the chair seat 14 when the chair assembly 2 is folded into its horizontal position as shown in FIG. 3.

When the chair assemblyZ is opened into its seating position, the amount of pivotal rotation of the chair seat 14 is limited by a stop member 42 positioned on each bracket 40 to engage the chair seat supporting arm 38 thereby preventing the seat from rotating beyond a substantially horizontal position. The stop member 42 is integrally fabricated with the bracket 40 and can best be seen in FIGS. 6 and 7.. This particular arrangement is of course but one way of limiting the pivotal movement of the chair seat and supporting arms and obviously other arrangements can be employed to maintain the seat in a horizontal position when the folding chair assembly is fully extended, 1

Each chair arm 16 is pivotally secured to bracket 36 by means of a short curved rod 44 rigidly attached to one end ofthe arm 16. Since the curved rod 44 is merely an extension of the chair arm 16 and bracket 36 is fixed with respect to the upright member, the chair arm 16 is appropriate edge of the chair back 12. This feature of the folding chair assembly facilitates the erection, disas-. sembly and maintenance of the folding chair seating I111 in effect pivotally secured to the upright member. Since other methods which vary only in detail can be employed to pivotally connect the chair arm to the upright member, it is not intendedtolimit the disclosed folding chair assembly to the particular configuration of the chair arm 16, rod 44, upright member brackets "36 and upright members illustrated in the drawings.

When the folding chair assembly 32 is opened to its seating position as shownin FIGS. 1"and'6, the chair arm 16 is maintained in a horizontal position by an intermediate, link "46- which is pivotally secured at one end to the chair arm 16 near the forward edge thereof and at the other end to the connecting link at a point intermediate of the ends of link 38. Referring to FIG. 3-, it can be seen that when the chair assembly 2 is folded into its horizontal or storage position the connecting link 30, intermediate link 46 and chair arm 16 lie in nested superposed relation. This relationship and the resulting reduction in the folded vertical dimension of the chair assembly are produced by the unique linkage arrangement of the chair assembly and the cross-sectional profile of the chair arm 16 and intermediate link 46. Both the arm 16 and link 46 are constructed with an elongated and inverted U-shaped cross-section so that link 30 will nest within the channel of the intermediate link 46 while the intermediate link nests in turn within the arm rest 16.

It has already been pointed out that the folding chair assembly 2 can be opened or closed by a single person with a minimum amount of effort. This is possible only because the friction between the various components of the folding chair assembly has been reduced to a minimum. Referring to the sequential opening of the chair assembly 2 as shown in FIGS. 3-6, it can be seen that the bottom surface of the chair seat 14 and the lower ends of the upright members 22 and 24 slide along the base 4. The frictional contact between these elements is lessened by utilizing rolling friction instead of sliding friction. Thus each chair seat 14 has a small roller 48 mounted therein with a portion of the roller 48 extending below the bottom surface of the chair seat 14 to provide a rolling contact with the base 4. The roller 48 can best be seen in FIGS. 7 and 8 along with a. ramp 50 which is mounted on the base 4 in alignment with the roller 48 (FIG. 8). As the chair assembly opens, the rounded forward edge 52 of the chair seat 14 strikes the ramp 48 thereby lifting the forward edge of the seat so that the edge will clear the pivot rod 32 as the seat moves forward (FIG. 5) while at the same time pushing the rear edge of the chair seat in a downward direction so that the roller 48 contacts the base 4. In this manner the rear edge of the chair seat 14 is in rolling frictional contact with the base 4 while the forward edge is in sliding frictional contact with the ramp 50. The forward chair seat edge 52 is rounded to reduce the frictional contact between the chair edge 52 and the ramp 48.

The frictional contact between the base 4 and upright members 22 and 24 is limited to rolling friction by mounting a wheel 54 within each upright member at the lower end thereof. As shown in FIGS. 3-5, the wheel 54 extends beyond the lower extremity of the upright member to provide rolling friction between the base 4 and each upright member;

It is apparent that the cooperative relationship between the forward chair seat edge 52 and the ramp 48 and the rolling friction of rollers 48 and wheels 54 significantly reduce the frictional contact between the components of the folding chair assembly 2, and hence, facilitates the erection of a multiple unit chair assembly by a single person. However, if the inherent advantages of the folding chair assembly are to be fully realized, the assembly must have a disengageable means for locking the chair in an upright position and if two or more chairs are mounted together, the locking means for each chair should be disengageable as a unit to eliminate the necessity of unlocking each individual chair before folding the unit.

Referring now to FIGS. 3, 4, 5, 6 and 7, the disengagea-ble locking means comprises a U-shaped channel member, indicated generally as 56, which is mounted on the base 4 in alignment with the corresponding upright member for engagement therewith during the erection of the folding chair assembly. Each channel member 56 has a bottom element 58 and two side walls 60 and 62 which extend upwardly from the bottom element 58. The rear edge of each side wall is tapered to form an inclined ram-p 64 with the base 4. In addition each side wall also has a slot 66 which extends downwardly from the upper edge of the side wall and in substantially parallel relation to the slope of the inclined ramp 64. Since each channel member 56 is aligned with a corresponding upright mem ber, the upright member will roll into the channel 56 when the chair assembly 2 is unfolded. Each upright member has a pair of outwardly extending lugs 68 and 70 which may be either integrally fabricated with the upright member or secured thereto by any well known method.

Referring back to the sequential opening of the folding chair assembly depicted in FIGS. 3-6, it can be seen that as each upright member rolls into the respective channel 56, lugs 68 and 78 will strike the inclined ramp 64 of side walls 60 and 62 thereby forcing the chair to pivot about the pivot point of the links 30 and bracket 36. Further pressure on the upper edge 18 of the chair back 12 (FIG. 5) forces the lugs onto the upper edge of the side walls 60 and 62 and then forwardly until the lugs engage the corresponding slots 66 as shown in FIG. 6. Once the lugs 68 and 70 have engaged the slots 66, the entire chair assembly 2 is rigidly held in an upright position. It is a feature of my invention that although the chair assembly is securely held in the upright position by the channel member 56 and lugs 68 and 70, the entire chair assembly can be collapsed merely by pulling on the lower edge 28 of chair back 12. As the lower edge 28 is pulled forward, the lugs 68 and 70 ride up the slope of the backing slots 66 until they are disengaged from the slots. At this point the lower edge 18 is lifted slightly and then pushed backwards to collapse the chair assembly.

If the chair assembly consists of more than one chair, e.g., the three chair unit shown in FIG. 1, the entire unit can be collapsed by pulling on the lower edge of one chair back, preferably the center chair. By pulling on the lower edge of the center :chair back, all of the chairs in the unit are disengaged from their respective channel members without requiring the worker to bend over and individually unlock each chair. This feature of my invention greatly simplifies the folding of the chair assembly and, hence, permits a single worker to fold a maximum number of chairs in a minimum amount of time.

It is also a feature of my invention that the chair assembly 2 cannot be collapsed from the rear. If pressure is applied to the back of the chair seat 12, as for example, by a youth placing his feet on the upper rear portion of the chair seat and pushing forwardly, the only effect on the chair assembly is to more securely lock the assembly in an upright position because the forward pressure on the upper portion of the chair back moves the lower portion of the assembly in a rearward direction thereby forcing the lugs 68 and 70 to seat more securely in the locking slots 66.

Since numerous modifications of the folding chair assembly will now be apparent to those skilled in the art, it is not my intention to confine the invention to the precise form shown herein, but rather to limit it in terms of the appended claims.

Having thus described and disclosed a preferred embodiment of my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A folding chair assembly collapsibly mounted on a base comprising: a frame having first and second upright members, said upright members each having a pair of lugs extending outwardly from said member normal to the longitudinal axis thereof; a wheel rotatably mounted on each upright member with a portion of said wheel extending below the lower end of said upright member; a chair back secured to said upright members; a chair seat having a rounded lower front edge, said seat being pivotally secured to said upright members; means for limiting the pivotal movement of said chair seat; a roller rotatably mounted in said chair seat with a portion of said roller extending below the lower surface of said seat; a ramp member mounted on said base in alignment with said roller whereby said roller contacts said ramp during the opening and closing of said collapsible chair assembly; first and second links each having one end thereof pivotally secured to said base and the other end thereof pivotally secured respectively to said first and second upright members; first and second chair arms each having one end thereof pivotally connected respectively to said first and second upright members above the pivot point of said links; first and second intermediate links each having one end thereof pivotally connected respectively to said first and second chair arms and the other end thereof pivotally connected respectively to said first and second links intermediate of the ends of said links; a plurality of channel members mounted on said base with the longitudinal axis of said channel members in alignment with corresponding upright members, said channel members" each comprising: a bottom element and. upwardly extending side Walls integrally fabricated therewith, said side walls each having the end thereof in proximity to said corresponding upright member tapered to form an inclined ramp with said base and a slot extending downwardly from the upper edge of said side wall in substantially parallel relation to said inclined ramp whereby when said chair assembly is' unfolded from its horizontal storage position said lugs will slide upwardly along the inclined ramp of said channel member walls and forwardly until the lugs engage the respective slots in said walls thereby locking said chair assembly in an upright position;

2. A folding chair assembly collapsibly mounted on a base comprising: a back member having lugs extending outwardly from the sides of the back member at the lower end thereof and a seat pivotally secured thereto, said back member being pivotally secured to the base by a single link on each side of the back member, said links having one end thereof pivotally secured to the back member, and the other end thereof pivotally secured to the base for rotation upwardly and forwardly from a substantially horizontal storage position to a seating position and forwardly and downwardly to a cleaning position; and 'releasable lug engaging means mounted on said base" for maintaining the back member in a substantially vertical seating position, said means comprising a plurality of upright lug engagingmembers mounted on said base in alignment with the correspondingback member lug, said lug engaging members having the end thereof in proximity tosaid corresponding lug tapered to form an inclined ramp with said base and a slot extending downwardly from the upper edge thereof in-substantially parallel relation to said inclined ramp whereby when said chair assembly is unfolded from its horizontal storage position to its seating position, said lugs will slide'upwardly along the inclined ramp'of the corresponding lug engaging member and forwardly until they engage its slot therein locking said chair assembly in a substantially upright seating position.

3. A folding chair assembly collapsibly mounted on a base comprising: a chair frame having first and second upright members, said upright members each having a pair of lugs extending outwardly therefrom; a chair back positioned between'and secured to said upright members; a chair seat pivotally secured to said upright members; chair arms pivotally secured to saidupright members; first and second links pivotally-secured atone end to said first and second upright members, respectively, and at the other end to said base for rotation upwardly and forwardly from a substantially horizontal storage position-to a seating position and forwardly and downwardly to a cleaning position; and releasable lug engaging means mounted on said base for maintaining said chair frame in a substantially upright seating position, said means comprising a plurality of channel-members mounted on said base with the longitudinal axis'of said channel members in alignment with the corresponding upright members, said channel members each'comprising: a bottom element and upwardly extending side walls integrally fabricated therewith, said side walls each having the end thereof in proximity to said corresponding upright member tapered to form an inclined ramp with said base and a slot extending downwardly from the upper edge of said side wall in substantially parallel relation to said inclined ramp whereby when said chair assembly is unfolded from its horizontal storage position, said lugs will slide upwardly along the inclined ramp of said channel member walls and forwardly until the lugs engage the respective slots in'said walls thereby locking said chair assembly in a substantially upright position.

References Cited by the Examiner UNITED STATES PATENTS FRANK B. SHERRY, Primary Examiner. 

1. A FOLDING CHAIR ASSEMBLY COLLAPSIBLY MOUNTED ON A BASE COMPRISING: A FRAME HAVING FIRST AND SECOND UPRIGHT MEMBERS, SAID UPRIGHT MEMBERS EACH HAVING A PAIR OF LUGS EXTENDING OUTWARDLY FROM SAID MEMBER NORMAL TO THE LONGITUDINAL AXIS THEREOF; A WHEEL ROTATABLY MOUNTED ON EACH UPRIGHT MEMBER WITH A PORTION OF SAID WHEEL EXTENDING BELOW THE LOWER END OF SAID UPRIGHT MEMBER; A CHAIR BACK SECURED TO SAID UPRIGHT MEMBERS; A CHAIR SEAT HAVING A ROUNDED LOWER FRONT EDGE, SAID SEAT BEING PIVOTALLY SECURED TO SAID UPRIGHT MEMBERS; MEANS FOR LIMITING THE PIVOTAL MOVEMENT OF SAID CHAIR SEAT; A ROLLER ROTATABLY MOUNTED IN SAID CHAIR SEAT WITH A PORTION OF SAID ROLLER EXTENDING BELOW THE LOWER SURFACE OF SAID SEAT; A RAMP MEMBER MOUNTED ON SAID BASE IN ALIGNMENT WITH SAID ROLLER WHEREBY SAID ROLLER CONTACTS SAID RAMP DURING THE OPENING AND CLOSING OF SAID COLLAPSIBLE CHAIR ASSEMBLY; FIRST AND SECOND LINKS EACH HAVING ONE END THEREOF PIVOTALLY SECURED TO SAID BASE AND THE OTHER END THEREOF PIVOTALLY SECURED RESPECTIVELY TO SAID FIRST AND SECOND UPRIGHT MEMBERS; FIRST AND SECOND CHAIR ARMS EACH HAVING ONE END THEREOF PIVOTALLY CONNECTED RESPECTIVELY TO SAID FIRST AND SECOND UPRIGHT MEMBERS ABOVE THE PIVOT POINT OF SAID LINKS; FIRST AND SECOND INTERMEDIATE LINKS EACH HAVING ONE END THEREOF PIVOTALLY CONNECTED RESPECTIVELY TO SAID FIRST AND SECOND CHAIR ARMS AND THE OTHER END THEREOF PIVOTALLY CONNECTED RESPECTIVELY TO SAID FIRST AND SECOND LINKS INTERMEDIATE OF THE ENDS OF SAID LINKS; A PLURALITY OF CHANNEL MEMBERS MOUNTED ON SAID BASE WITH THE LONGITUDINAL AXIS OF SAID CHANNEL MEMBERS IN ALIGNMENT WITH CORRESPONDING UPRIGHT MEMBERS, SAID CHANNEL MEMBERS EACH COMPRISING: A BOTTOM ELEMENT AND UPWARDLY EXTENDING SIDE WALLS INTEGRALLY FABRICATED THEREWITH, SAID SIDE WALLS EACH HAVING THE END THEREOF IN PROXIMITY TO SAID CORRESPONDING UPRIGHT MEMBER TAPERED TO FORM AN INCLINED RAMP WITH SAID BASE AND A SLOT EXTENDING DOWNWARDLY FROM THE UPPER EDGE OF SAID SIDE WALL IN SUBSTANTIALLY PARALLEL RELATION TO SAID INCLINED RAMP WHEREBY WHEN SAID CHAIR ASSEMBLY IS UNFOLDED FROM ITS HORIZONTAL STORAGE POSITION SAID LUGS WILL SLIDE UPWARDLY ALONG THE INCLINED RAMP OF SAID CHANNEL MEMBER WALLS AND FORWARDLY UNTIL THE LUGS ENGAGE THE RESPECTIVE SLOTS IN SAID WALLS THEREBY LOCKING SAID CHAIR ASSEMBLY IN AN UPRIGHT POSITION. 